U2403B Datasheet, PDF (2/12 Pages) TEMIC Semiconductors – Charge Timer

U2403B
Pin Description
V₁ 1
V₂ 2
Sense 3
Osc 4
8 LED
7 GND
6 V_S
5 S_TM
Pin Symbol
Function
1
V₁ Collector terminal
2
V₂ Shunt emitter terminal
3
V₃ Amplifier sense input
4
Osc Oscillator input
5
S_TM Test mode switch
6
V_S Supply voltage
7
GND Reference point, GND
8
LED Charge mode indicator
94 8685
Pin 1, Collector Voltage V₁
Pin 1 is an open collector output. When V₁ ≤ 3 V, the
charge cycle is switched off until it is above the supply
voltage, as shown in figure 6.
Pin 2, Shunt Emitter
1
2
3
Pin 4 Oscillator
256
Pulse
The constant current source is supplied by the internal
operational amplifier. The voltage across R₃ is deter-
mined via the internal reference source.
I_ch = V₃/R₃ (V₃ = V_sense)
Pin 3, Amplifier Sense Input (Inverted)
Pin 5 Test – Mode
94 8839
Figure 2. Quick test timer 1/3
The voltage-regulated current source has a closed loop at
Pin 2, Pin 3, and resistor R₃.
Pin 4, Oscillator Input R₄, C₄
Selection of current charge versus timing is carried out by
using the external circuit at Pins 2, 3, and 4. Typical
values are given in charge characteristics (see table next
page).
Pin 5, Test-Mode Switch for Charging Time
The charging time, t_ch, is given by the following equation.
+ t_ch
1
f_osc
2ⁿ
where:
f_osc = oscillator frequency (see figure 2)
n = frequency divider
= 26, if S_TM open
= 17, if S_TM = GND
= 8, if S_TM = V_S
The first eight divider stages can be tested directly.
256 input tact signals at Pin 4 create one tact signal at
Pin 5.
Example
Assume a charge time of 6 h.
Select the values of R₄ and C₄ from the tables next page.
For example:
W R₄ = 470 k
C₄ = 680 pF
There is a frequency of approximately 3100 Hz at Pin 4.
It is possible to test the charge time of 6 h by running
through the charge cycle for a very short time. By
connecting Pin 5 with GND, the test time is 42 s. By
connecting Pin 5 with Pin 1 (V₁), the test time is reduced
to about 82.4 ms. R₅ is connected in parallel to the LED₂
and provides a protective bypass function for the LED
(see figure 1).
Pin 6, Supply Voltage, V_S
[ V_S 3.1 V power-on reset release (turn-on)
[ V_S 2.9 V under-voltage reset
[ V_S 13 V supply voltage limitation
Pin 7, Ground
2 (12)
TELEFUNKEN Semiconductors
Rev. A1, 20-Mar-96